You can use SAS, or Side Angle Side. Because BC equals EC and AC equals DC, you can get two sides. Also, angle BCA and DCE have the same angle measurement, so you can conclude, using SAS, that BA equals to ED. Also, you can also prove that these two triangles are congruent and that all of the angles are the same as well because all of the side lengths are equal.
Answer b 26 because a squared plus b squared = c squared so 10x10 + 24x24 = 676 and so you take the square root of 676 which is 26.
